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If you feel dizzy, lightheaded and weak during the summer, you may be suffering from seasonal low blood pressure. Find out more about why blood pressure drops when temperatures rise, and what you can do about it.

Are you feeling weak, dizzy, and lightheaded? If that's a regular occurrence for you during the summer, you may think of these unpleasant symptoms as a normal side effect of warmer weather. If you're on holiday, meanwhile, you may attribute your symptoms to jet lag, alcohol, or a simple lack of sleep. Think again. It's quite likely that you're suffering from seasonal hypotension — low blood pressure brought on by warmer weather.

How do seasons affect blood pressure, is hypotension dangerous, what are the symptoms and what can you do about it? Read on to find out more.

How Seasons Affect Blood Pressure

Seasonal changes in blood pressure are rarely talked about. That's surprising, because there is plenty of evidence that blood pressure rises in winter and drops during the summer. This is true for people of all ages groups and both genders, and happens even if your blood pressure is generally already too low or too high. It even happens to people who take medication for high blood pressure.

Why does this happen? The consensus is that blood vessels narrow in colder weather, while they relax when the temperature shoots up. Additionally, the extra sweating associated with warmer weather leads to fluid and salt loss, causing blood pressure to drop even further.

Despite the fact that this phenomen was first observed as far back as 1920 and numerous studies have since been conducted to find out more about seasonal blood pressure changes, few people are aware of the possibility that this might happen. Hypertension patients, who tend to measure their blood pressure regularly, are perhaps most likely to be aware of the way in which their blood pressure changes with the weather.[1]

Hypotension: The Symptoms

The idea that neither high nor low blood pressure leads to symptoms is another very prevalent misconception. Many people do indeed notice changes in their blood pressure. That doesn't mean they're aware of the cause of their symptoms, of course. Blood pressure refers to the pressure in your arteries during both the resting and active phase of your heart beat. Systolic pressure, the top number on a blood pressure reading, refers to pressure while the heart is beating. Diastolic, the bottom number, refers to the pressure during the resting phase.

Your blood pressure may be considered to be too low if your systolic pressure is 90 mm Hg or lower, or (not and!) your diastolic pressure is equal to or below 60 mm Hg. Some doctors will not consider this to be a problem unless you do have symptoms, however.

These symptoms are highly unpleasant and can make daily life difficult. It's important to be aware of the fact that low blood pressure can be caused by medical conditions. Some, like pregnancy and dehydration (more common in summer, for obvious reasons) are temporary. Others, like heart disease and hormonal disorders, are not. Low blood pressure may also be a side effect of nutritional deficiencies. Though high blood pressure is much more commonly recognized as a condition that can jeopardize your health, it is clear that low blood pressure deserves to be taken seriously as well.